Low-density Lipoprotein Cholesterol Size Research Articles

Higher levels of small dense low‐density lipoprotein (LDL) are associated with cardiac autonomic neuropathy in patients with Type 2 diabetes

To investigate the relationship between small dense LDL cholesterol and cardiac autonomic neuropathy among patients with Type 2 diabetes. A total of 175 patients who had not taken lipid-lowering agents previously were enrolled consecutively in this study. Small dense LDL cholesterol level was measured using polyacrylamide tube gel electrophoresis, which fractionates LDL cholesterol into seven components according to particle size and charge. We analysed the mean LDL cholesterol particle size and the proportion of small dense LDL cholesterol. The mean (± sd) patient age was 56 (± 14) years, the mean (± sd) duration of diabetes was 10.3 (± 8.3) years, the mean (± sd) proportion of small dense LDL cholesterol was 21.3 (± 17.6)% and the mean (± sd) LDL cholesterol size was 26.33 (± 0.8) nm. Men with cardiac autonomic neuropathy had a longer duration of diabetes compared with those without cardiac autonomic neuropathy. Women with cardiac autonomic neuropathy had a larger waist circumference, higher plasma triglyceride levels, smaller mean (± sd) LDL cholesterol size [26.8 (± 4.3) nm vs 26.4 (± 6.9) nm; P < 0.01] and larger mean (± sd) proportion of small dense LDL cholesterol [10.1 (± 9.9)% vs 19.1 (± 16.8)%; P < 0.01] compared with those without cardiac autonomic neuropathy. After adjusting for other confounding risk factors, the triglyceride/ HDL cholesterol ratio (odds ratio = 1.698, 95% CI: 1.07-2.69; P = 0.025) and mean LDL cholesterol size (odds ratio = 0.873, 95% CI: 0.77-0.99; P = 0.038) remained as independent risk factors for cardiac autonomic neuropathy in women. A more atherogenic lipid profile such as the triglyceride: HDL cholesterol ratio and a smaller mean LDL cholesterol particle size were related to the prevalence of cardiac autonomic neuropathy in women with Type 2 diabetes.

Exercise effects on lipids in persons with varying dietary patterns—does diet matter if they exercise? Responses in Studies of a Targeted Risk Reduction Intervention through Defined Exercise I

The standard clinical approach for reducing cardiovascular disease risk due to dyslipidemia is to prescribe changes in diet and physical activity. The purpose of the current study was to determine if, across a range of dietary patterns, there were variable lipoprotein responses to an aerobic exercise training intervention. Subjects were participants in the STRRIDE I, a supervised exercise program in sedentary, overweight subjects randomized to 6 months of inactivity or 1 of 3 aerobic exercise programs. To characterize diet patterns observed during the study, we calculated a modified z-score that included intakes of total fat, saturated fat, trans fatty acids, cholesterol, omega-3 fatty acids, and fiber as compared with the 2006 American Heart Association diet recommendations. Linear models were used to evaluate relationships between diet patterns and exercise effects on lipoproteins/lipids. Independent of diet, exercise had beneficial effects on low-density lipoprotein cholesterol particle number, low-density lipoprotein cholesterol size, high-density lipoprotein cholesterol, high-density lipoprotein cholesterol size, and triglycerides (P < .05 for all). However, having a diet pattern that closely adhered to American Heart Association recommendations was not related to changes in these or any other serum lipids or lipoproteins in any of the exercise groups. We found that even in sedentary individuals whose habitual diets vary in the extent of adherence to AHA dietary recommendations, a rigorous, supervised exercise intervention can achieve significant beneficial lipid effects.

Reverse Epidemiology of Lipid-Death Associations in a Cohort of End-Stage Renal Disease Patients

Background and Aims: Cardiovascular disease is the leading cause of death among end-stage renal disease (ESRD) patients with hypercholesterolemia as a major cause. A few studies have demonstrated counter-intuitive findings known as reverse epidemiology where normal levels of cholesterol are associated with higher levels of mortality. The purpose of this study was to determine if there are reverse epidemiological associations between lipid risk factors and mortality in ESRD patients. Methods: ESRD (n = 438) patients were recruited from 4 outpatient dialysis units. Patients were tracked for 36 months until study completion or death with mortality status as the outcome measure. Results: Analysis of covariance revealed significant differences at posttest and reverse epidemiological effects for total cholesterol (p = 0.0001), low-density lipoprotein cholesterol (LDL) (p = 0.023), LDL particle number (p = 0.0001), LDL size (p = 0.009), triglycerides (p = 0.0001), and very low-density lipoprotein cholesterol (p = 0.036). A step-wise linear regression revealed weak, but significant predictors of mortality with total cholesterol (β = 0.263, p = 0.017) and LDL (β = –0.177, p = 0.045). A Cox death hazard ratio revealed LDL size as a significant predictor of mortality in this study. Conclusions: Our study discovered reverse epidemiology in a number of lipid variables. Additionally regression revealed that LDL and total cholesterol were predictors of mortality with lower levels being more predictive of death.

Growth Hormone Deficiency in Adults

Adults with Growth hormone (GH) deficiency is now being recognised to display many distinct clinical, metabolic and psychological abnormalities. It has been demonstrated that GI-I deficient (GHD) adults display features of multiple insulin resistant syndrome (MIRS) which predispose the GHD adults to increased cardiovascular morbidity and mortality. These features include central obesity, insulin resistance and glucose intolerance, hypertension, dyslipidaemia that includes a reduced level of high density lipoprotein cholesterol, an elevated triglyceride level and small low density lipoprotein cholesterol size. Furthermore, GHD adults are found to have a lower bone mass and a reduced sense of well-being. Replacement of GH in these GHD adults has brought about a major improvement inpsychological well-being and central obesity. The improvement of some of the lipid abnormalities is however more modest. Insulin resistance, the corner stone of MIRS, is however not altered by GH replacement. Long term data is as yet unavailable to assess if GH replacement reduces cardiovascular mortality and morbidity in these subjects.